Drier and method for the manufacture of gelatinous substances



Nov 20, 1934. T. K. LOWRY 1,981,806

DRIER AND METHOD FOR THE MANUFACTURE OF GELATINOUS SUBSTANCES Filed June28, 1929 2 Sheets-Sheet 1 X ill: I S.

DRIER AND METHOD FOR THE MANUFACTURE OF GELATINOUS SUBSTANCES T. K.LOWRY Nov. 20, 1934.

Filed June 28, 1929 2 Sheets-Sheet 2 Patented Nov. 20, 1934 UNITEDSTATES PATENT OFFICE DRIER AND METHOD FOR, THE MANUFAC- TURE OFGELATINOUS SUBSTANCES Application June 28, 1929, Serial No. 374,524

18 Claims.

especially when the same have been formed into small pellets.

Another object of the invention is to provide a new and improved methodof drying glue that will decrease the time necessary to thoroughly drythe glue. This method contemplates partially drying the glue with coldair and thereafter applying heated air at a temperature which will drythe glue without causing the same to revert back to its liquid state.

Another object of this invention is to provide an improved method andapparatus for drying glue, which comprises the steps of first forming anon-adhesive coating on the outer surface thereof in the form of a thinskin by means of a blast of relatively cool air or other drying mediumand thereafter successively subjecting the glue to warmer mediumswhereby the moisture of the glue is driven therefrom.

Another object of this invention resides in pro-' viding a new anduseful method of drying glue, which contemplates the drying of pelletsofappreciable size and thickness by first jellifying the glue andsubsequently producing first a thin skin on the outer surface of thepellets by a drying medium conditioned to a temperature which will notmelt the glue and cause the same to revert to a liquid state, andthereafter subjecting the pellets to increased temperatures to drive themoisture from the glue, the glue being prevented from reverting to itsliquid state after the first step of drying because of the thin skinformed, which skin will not break down under the influence of increasedtemperatures of the drying mediums at successive stages of the dryingprocess.

Still another object of the invention is the provision of a compactconveying apparatus for.

conveying the glue into contact with the various drying fluids ormediums and providing an agitating apparatus which will keep the pelletsof glue from adhering to each other or to the conveyer while they arestill in a somewhat adhesive state.

Finally, the invention has for its object the provision of novel meansfor giving the right temperatures to the drying mediums used.

In the drawingsz- Fig. 1 represents a side elevation of a conveyermechanism embodying my invention;

F Fig. 2 is a cross section on the line 22 of Fig. 3 is a pl. n view ofthe apparatus'shown in Fig. 1; and

Fig. 4 is a diagrammatic view of the mechanism for reversing the motor.

The apparatus shown comprises a plurality of conveyers 1, 2 and 3adapted to support the pellets of glue while they are being dried andforms a means for conveying said pellets into contact with the variousdrying fluids or mediums. The conveyer 1 is supported upon the rotatabledrums 4 and 5 and idle rollers 12. Similarly, the conveyer 2 issupported by means of the drums 6 and 7 and idle rollers 13. Theconveyer 3 is supported by drums 8 and 9 and idle rollers 14. Theconveyers 1 and 3 move in the same direction which, in the embodimentshown, is to the left, while the conveyer 2 moves in the oppositedirection, or to the right in the embodiment shown, as will be seen bythe arrows in Fig. 3.

A drive shaft 23 furnishes the power to drive the conveyers in thespecified directions. A chain 11 directly connects the shaft 23 to theshaft upon which the drum 8 is rotatably mounted. The'gears 10 and 10,mounted respectively on the'shaft which carries the drum 6 and on theshaft 23, are adapted to drive the drum 6 in a direction opposite tothat of the drum 8 and the drum 4, the latter being mounted directlyupon the drive shaft 23.

Mounted directly over the conveyer 1 are a plurality of interconnectedhoods 16 which form a covering for substantially enclosing the upper runof the conveyer 1. These hoods are all connected to a common outlet pipe17 by means of suitable conduits, as shown in Fig. 1. A conduit 1-8forms a common inlet for the plurality of hoods which cover theconveyer 1. A drying' 'fluid or medium, preferably air, is introducedinto-the hoods through the conduit 18 below the upper run of theconveyer 1. This conveyer is formed of a suitable wire mesh or screeningso that the drying fluid passes upwardly through the conveyer and in andaround the pellets of glue which are supported upon the conveyer, thuscausing the drying fluid to have a more intimate contact with the gluepellets. This lessens the time necessary for drying the glue. m

The conveyer 2 has the upper run thereof passing through the conduit 19which is open at the,

the upper run of the belt. The drying medium,

passes through the perforate conveyer and through the open top of theconduit, thus providing a very eflicient means for circulating thedrying medium around the pellets on the conveyer. An inlet 22 provides ameans whereby a drying medium is introduced into the conduit 21 belowthe conveyer 3, the conduits 19 and 21 operating in substantially thesame manner but using drying mediums at different temperatures. Thepellets of glue are formed just prior to placing the same upon theconveyer 1 and at the time when they are received by the conveyer 1,they are in a more or less adhesive condition so that they have atendency to stick together. In order to prevent this, I provide meansfor agitating the pellets while on the conveyer 1. This means comprisesa pair of sprocket wheels 27 and28 which carry the chains 42 which havethe cross bars 43 connected to opposed links thereof. Each of theselinks carries a plurality of teeth 44 arranged in staggered relation onopposite sides of each of said members 43. It is to be understood thatthe teeth 44 on each of the bars 43 are staggered with respect to theteeth on adjacent bars and in a direction longitudinally of the conveyer1 so that as the teeth move through the pellets of glue on the conveyer1, they will not merely form tracks through the pellets, as would be thecase where the teeth were all in alinement longitudinally of theconveyer 1.

Suitable means is provided for rotating the sprockets 2'7 and 28 andthis means comprises a source of power independent from the source ofpower which drives the shaft 23. This independent sourceof power may bea motor 25 provided with a suitable reversing switch for reversing thedirection of rotation thereof for a purpose later to be described.

In the embodiment shown, I provide a chain 26 which is trained oversuitable sprockets on the shafts 24 and 28', the latter shaft alsocarrying the sprockets 28. This provides a positive drive for both thesprockets 27 and the sprockets 28. However, it is to be understood thatthe chain 26 may be omitted since the shaft 28' will be rotated due tothe chains 42 being trained over both the sprockets 2'7 and 28.

The chains 42 may be moved continuously in one direction if desired butI prefer to have these chains move alternately in first one directionand then the opposite direction so as to keep the pellets of glue frompiling up at one end of the conveyer in case the movement of theconveyer should be stopped for any reason and there is a tendency todrag the pellets along faster than the conveyer when the conveyer is inoperation.

By providing a separate motor 25, the chains 42, and, consequently, theteeth 44, may be kept moving even though the movement of the conveyer 1has been stopped. In order to reverse the direction 01' movement of thechains 42, I provide the lugs 45 on one of the chains 42. I also providea. pivoted lever 46 having a projection 4'7 thereof extending through aslot 48 into the closed chamber formed by the hoods 16. The projection4'7 is so arranged as to be in the path of movement of the lugs 45. Asthe lugs 45 come into engagement with the projection 47, the lever 46 isrocked about its pivot and the lower end of the lever engages one of thelugs 48 on the rotatable member 49 rigidly fastened to the shaft 50 andthis causes a slight rotation of the rotatable member 49'and also of theshaft 50. The rotation of the shaft 50 actuates any suitable type ofreversing switch for the motor 25 and in Fig. 4 there is showndiagrammatically a means for accomplishing this result. This meanscomprises an arm .44 secured to the shaft 50 and a link 45' operativelyconnected to a reversing switch indicated by the reference numeral 46,the reversing switch being of the pole changing type common toelectrical apparatus. The power circuit for the motor is indicated at 47and the leads to the motor at 48. It will be obvious that as therotatable member 49 is alternately rocked in opposite directions thecurrent will fiow through the motor in opposite directions for thepurpose of reversing the direction of rotation thereof. It will beunderstood, of course, that any other desired reversing means for thechains 42 may be used. Also, it is possible to use only one lug 45 withthe reversing mechanism as this lug will engage opposite sides of theprojection 4'7 to cause the lever 46 to operate the reversing switch inthe manner previously described.

By the use of the agitating means just described, it will be noted thateven though movement of the conveyer 1 is stopped, the teeth 44 on thebars 43 will continue to agitate the pellets of glue thereon and willnot cause the pellets to pile up at one end or the other of the conveyerdue to the fact that the tendency of the teeth 44 is to move the pelletsfirst in one direction and then the other longitudinally of the conveyerduring opposite movements of the chains 42. It will be understood, ofcourse, that any other desired means may be used to agitate the pelletsof glue on the conveyer 1. Pellets of glue are formed substantially inthe manner described in my co-pending application, Serial No. 349,032filed March 22, 1929 and these pellets fall or are otherwise positionedon the conveyor 1 at the extreme right hand portion thereof as viewed inFig. 1. This glue is relatively cool and sticky and a thin skin shouldbe formed on the outer surface thereof before the glue can be subjectedto any great amount of drying action. I therefore subject the glue firstto a relatively cool drying medium to form a thin skin on the outersurfaces of the pellets, for if a warm drying medium were appliedthereto, the jelled glue would immediately revert to a liquid state andof course thereby prevent any further drying of the glue and render itimpossible to operate the drying apparatus as intended. A conduit 29leads from the common outlet pipe 17 into a refrigerating apparatus 33which has another conduit 33 connected to a blower 30. This blower 30 isso arranged as to draw the drying medium through the conduit 33', andblow it through the heating chamber 31, conduit 18 and conveyer belt 1,in and around the glue on the conveyer belt, and then into the hoods 16,the heating chamber 31 having a suitable heating coil 32 therein. Thisheating coil may be constructed in any suitable manner such as by meansof a coiled pipe which has a heating means, such as hot water or steam,passing therethrough, or, if desired. it may be an electrical heatingelement.

It will be seen that by the arrangement just described, a substantiallyclosed circuit is provided for the drying medium supplied to the glue onthe conveyer 1 so that the same drying medium is used over and overagain. As the drying medium passes through the refrigerating chamber, 33its temperature is lowered and, as a result, some of the moisturetherein is deposited in the chamber 33 before it passes through theconduit 33' to the blower 30. As the drying medium passes through theheating chamber 31, its temperature A used as a drying medium in .the

is raised slightly but not to an extent that will make it be considereda warm drying medium, as its temperature, after it leaves this chamber,is still quite low, but by cooling it in the chamber 33, where some ofits moisture is deposited, and then heating it again a slight amount,the drying medium acquires considerably more drying power as it iscapable of taking on more moisture. Therefore, as the drying mediumpasses through the pellets of glue mounted on the conveyer 1, it canabsorb moisture therefrom to hasten the drying thereof. As the dryingmedium again returns to the chamber 33, some of the moisture is againdeposited therein, and as soon as it is again heated in the chamber 31,it is capable once more of absorbing some of the moisture in the gluepellets on the conveyer 1.

The purpose of supplying a substantially'cool drying medium to thepellets on the first conveyer is to do the preliminary drying at atemperature which will not permit the glue to go back to a liquid state.A dry skin is formed around the outside of glue particles in thisoperation; After this has been done, a warmer heating medium may beapplied thereto to cause said pellets to be more quickly dried.

The upper run of the conveyer 1 is moving toward the left, as seen inFig. 1, and, as the pellets of glue thereon leave the last of the hoods,they are carried over the drum 4 and drop onto the conveyer 2, locateddirectly therebeneath, the conveyer 2 being made slightly longer thanthe conveyer 1 for this purpose. The pellets are then carried by theconveyer 2 between the opposed walls 19' of the conduit 19 into which awarmer drying medium is introduced below the conveyer 2 by means of theblower 15 which draws air into the chamber 37 and forces it through theconduit 20 into the conduit 19. The chamber 37 has a heating coil 38therein which heats the air when it is driven by the blower 15 into theconduit 19. After the pellets of glue have reached the extremeright-hand portion of the conveyer 2, as seen in Fig. 1, they arecarried over the drum '7 and fall onto the conveyer 3 locatedtherebeneath. Thereafter, these pellets are carried between the opposedwalls 21' of the conduit 21 into which a drying medium is introduced ata temperature higher than that of the drying medium in the conduit 19.The drying medium is introduced into this conduit 21 by means of ablower 22 which draws the drying medium through the chamber 39 andforces it.

through the conduit 22 into the conduit 21. A suitable heating coil 40is mounted in the chamber 39 for heating the drying medium therein tothedesired temperature. After the pellets of glue have reached the extremeleft-hand portion of the upper run of the conveyer 3, they are carriedover the drum 8 onto any suitable receiving device which may be desired.It is to be understood that the pellets are formed in any suitablemanner prior to being placed upon the conveyer 1.

Although a closed circuit is provided for the drying medium supplied tothe hods 16, it may be found desirable, for the sake of economy, to cutout the refrigerating apparatus 33 when the temperature, either of theairsurrounding the apparatus the apparatus is located, is suflicientlylow to be hoods 16. In order to do this, the blower 30 is provided withan auxiliary conduit 35 connected to the outside atmosphere and thisconduit has a damper 35' arranged therein to close this conduit when theor that outside of the building in whichclosed circuit, previouslydescribed, is being used. The common outlet pipe 17 is also providedwith a damper 34 which is closed while the closed circuit is being used.When, it is desired to use the outside atmosphere as the drying medium,the damper 35' is opened as is also the damper 34 and the damper 36 isclosed so that that part of the apparatus which comprises the conduit29, refrigerating apparatus 33 and conduit 33', is no longer in use. Itwill readily be seen that by providing a device which can use theoutside atmosphere when it is at or below the temperature desired, thecost of maintaining the refrigerating apparatus is done away with andthe cost of operation of the device is greatly lessened.

Suitable guard members 41 are provided for each conveyer and are locatedadjacent the edges of the conveyers 1, 2 and 3 to prevent the pellets ofglue on the conveyers from dropping down between the edges of theconveyers and the adjacent sides of the member 16, 19 and 21. Thesemembers 41 also seal the opening between the edges of the conveyers andthe adjacent sides of the members 16, 19 and 21, so as to cause thedrying medium to pass through the perforate conveyers 1, 2 and 3 and donot permit any of the drying medium to leak past the edges of theconveyers, since, obviously, any of the drying medium circulating pastthe edges of the conveyer would not have any appreciable drying effectupon the glue but would merely pass into the hoods 16 or into theatmosphere.

By drying the glue while it is in the form of small pellets, a greaterdrying surface per unit volume is obtained than where fiat slabs of glueare used, as in prior known processes wherein long drying alleys areused and in which the slabs are stacked oncars or trucks which carry theslabs through the alleys. The rate of drying of the glue is a functionof the surface per unit volume exposed to the drying medium, and it willbe readily seen that with a device constructed according to thisinvention, the time required for drying is considerably lessened, due tothe form of the glue being dried. In addition, the novel apparatusdescribed insures a quicker drying of the glue even where the glue beingdried is not in the form of small pellets.

The device is shown with the conveyers arranged one above the other butthis has been done purely for the sake of convenience and for thepurpose of providing a compact arrangement which can be placed in a verysmall area. This is an advantage over the old drying alleys which werepreviously used and which required considerable area for installation.It will be understood that other arrangements may be made for theconveying mechanism without departing from the spirit of this invention.The second and third conveyors preferably will be so arranged, however,as to receive the pellets by gravity from the preceding conveyor. Theconveying mechanism may also be arranged in any suitable manner or beconstructed in other ways than indicated as long as there is a meansprovided for subjecting the glue to distinct quantities of dryingmediums or distinctly different conditioned quantities of a dryingmedium.

With the old types of drying apparatus, the time required for dryingwasfrom three ,days to a week whereas with the present device, it is onlynecessary to keep the glue on each conveyer for approximately two to sixhours, making a total of approximately six to eighteen hours tothoroughly dry the glue, depending on the grade of glue and thecondition of the drying medium. The advantages arising from the savingof time are obvious and for this reason it will be seen that the presentdevice is far superior to the prior devices, with which I am familiar.

When the glue reaches the left-hand end of the conveyer 3, it is quitehot and is in a somewhat sticky state which makes it difllcult tohandleand, if desired, a fan 60 can be arranged underneath the conveyer 3 todirect a blast of cool air through the belt to cool the glue thereon. Ahousing 61 directs the blast of air against the pellets in order tobring the same into proper contact with the glue, the housing beingpreferably arranged so that the blast of air passes through the conveyorfrom the underside thereof. This changes the surface of the glue so thatit is no longer sticky and can then be readily handled. Or, if desired,the cooling medium can be directed on the glue after the glue leaves theconveyer.

The present device is not limited to having the glue subjected todistinct changes in temperature and it is understood that the changefrom a low temperature to a high temperature may be a gradual one, ifdesired.

While the conveyers 2 and 3 are each provided with conduits which areopen at the top, it is to be understood that, if desired, the conveyers2 and 3 may be closed circuits such as that illustrated for the conveyer1.

Obviously, those skilled in the art may make various changes in thedetails and arrangement of parts without departing from the spirit andscope of the invention as defined by the claims hereto appended and Itherefore do not wish to be restricted to the precise constructionherein disclosed.

Having thus fully disclosed an embodiment of my invention, what I claimand desire to secure by Letters Patent of the United States is:

1. The method of drying glue pellets which comprises the steps ofsubjecting the pellets to a conditioned drying medium substantiallyfree,

from moisture and simultaneously agitating the pellets to prevent thepellets from adhering to each other and to form a non-sticky surface oneach of said pellets.

2. A pellet glue drying apparatus including a movable longitudinallydisposed and perforated conveyor for receiving pellets to be dried,means for moving said conveyor, agitating means mounted in the vicinityof said conveyor, said agitating means being adapted to move in oppositedirections along a given path, whereby pellets positioned at a givenlocation on the conveyor may be engaged in opposite directions by saidagitating means, means for moving said agitating means in oppositedirections longitudinally of the conveyor, and means for supplyingadrying medium to the pellets carried by said conveyor.

3. The method of drying glue pellets which comprises the steps ofsubjecting the pellets to a relatively cool drying medium substantiallyfree from moisture and conditioned to form a surface on the pelletswhich will prevent their adhering to each other, and simultaneouslyagitating the pellets while they are subjected to the action of,

said drying medium.

4. The method of drying glue pellets which comprises the steps ofagitating the pellets while on a supporting surface, subjecting saidpellets to the action of an unsaturated drying medium conditioned to atemperature to form a substantially non-adhesive coating on the outsideof said pellets and thereafter subjecting said pellets to 9.

drying medium conditioned to thoroughly dry the same.

5. A glue drying apparatus for drying glue pellets comprising a conveyorfor conveying glue pellets continuously in one direction along apredetermined path, an endless flexible element having a run thereofsubstantially parallel to said conveyor and carrying a plurality ofagitating means arranged over said conveyor and moving through thepellets while on said conveyor for agitating said pellets, and means formoving said endless flexible element in opposite directions andindependently of the movement of the conveyor.

6. Glue drying apparatus comprising means for conveying pellets along apredetermined path, separate means for supplying a heating medium to thepellets at difierent positions along said path, a conduit for conveyingthe heating medium from the pellets at the first of said positions afterit has been in contact with the pellets, a chilling means into whichsaid drying medium is conveyed by said conduit, means for directing saiddrying medium through a heating unit after it passes through saidchilling means, means for returning said drying medium to said conveyerafter it has 1 passed through said heating unit, and means for cuttingoff communication between said heating medium and said chilling meanswhen desired, and additional conduit means communicating with theatmosphere and said heating unit to supply a 1C5 drying medium to saidheating means when said last mentioned means is operative, whereby theair from the surrounding atmosphere, if at a sufiiciently lowtemperature, may be used in place of said chilled drying medium tosupply said heat- 11' ing unit, agitating the pellets while at saidfirst drying position, and means for conditioning a heating medium to besupplied to said pellets at each of the remaining positions throughwhich the pellets pass while moving along said path, said heatingmediums supplied at successive positions being at higher temperaturesthan at said first position.

7. The method of drying jellified glue pellets and the like whichcomprises the steps of moving a bed of pellets along a predeterminedpath through diilerent drying positions, passing unsaturated air throughsaid bed of pellets into intimate contact with said pellets at the firstof said positions, said air being at a temperature which is notsufiiciently high to melt said pellets, whereby the outer surfaces ofsaid pellets are dried to form a skin thereon before the same aresubjected to a later stage of drying, simultaneously agitating thepellets in said bed to prevent the same from cohering, and passingunsaturated air through said bed of pellets at a subsequent one of saidpositions, the said air being at a higher temperature than the airsupplied to the glue at said first position.

8. The method of drying jellified glue pellets and the like whichcomprises the steps of moving a bed of pellets along a predeterminedpath through different drying positions, passing unsaturated air throughsaid bed of pellets into intimate contact with said pellets at the firstof said positions, said air being at a temperature which is notsufiiciently high to melt said pellets, whereby the outer surfaces ofsaid pellets are dried to form a skin thereon before the same aresubjected to a later stage of drying, simultaneously agitating thepellets in said bed to prevent the same from cohering, passingunsaturated air through said bed of pellets at a subsequent one of saidpositions, the said air being at a higher 1 temperature than the airsupplied to the glue at said first position, and passing unsaturated aat a still higher temperature than at either of said first two mentionedpositions through said bed of pellets at a third subsequent position insaid path of travel of said pellets to thoroughly dry said glue.

9. The method of drying glue pellets and the like by conditioned airafter they have been put in a jellified condition which consists, inmoving the pellets along a predetermined path through successive dryingpositions, cooling the air to be supplied to said glue at the firstposition to remove the moisture therefrom, subsequently heating the aira substantial amount above the temperature at which the same was cooledwithout the addition of moisture thereto to a temperature which isinsuflicient to cause said pellets to melt when said air contacts withthe same but is high enough to cause a substantial transfer of moisturefrom the glue to the air, supplying said heated air to said jellifiedpellets at the'flrst position thereof for a time suflicient to form aprotective skin on the same, simultaneously agitating the pellets whilethey are subjected to'the drying action of said air, and thereaftersubjecting the pellets at a subsequent position to a higher temperaturefor removing the remaining moisture from the interior of the pellets.

10. The method of drying glue pellets and the like by conditioned airafter they have been put in a jellified condition which consists inmoving the pellets along a predetermined path through successive dryingpositions, removing the moisture from the air to be supplied to saidglue at the first position, cooling the same to a temperature at whichthe air is to be supplied to the pellets for drying purposes,subsequently heating the air without the addition of moisture thereto toa temperature which is insuflicient to cause said pellets to melt whensaid air contacts with the same, but is sufliciently high to cause arapid transfer of moisture from the glue to the air, moving the pelletsalong a predetermined path, supplying said heated air to said jellifiedpellets at the first position thereof for a time suflicient to form aprotective skin on the same, agitating said pellets substantially at allpoints along the path of movement of said pellets irrespective ofwhether said pellets are in motion along their path to prevent caking ofthe pellets and to permit them to come in contact with the pellets, andthereafter subjecting the pellets at a subsequent position to a highertemperature for removing the remaining moisture from the interior of thepellets.

11. The method of drying glue pellets and the like by conditioned airafter they have been put in a jellified condition which consists inmoving the pellets along a predetermined path through successive dryingpositions, removing the moisture from the air to be supplied to saidglue at the first position, cooling the same to a temperature below thetemperature at which the air is supplied to the pellets for dryingpurposes to thereby remove moisture from the air above the saturationpoint of the air at the temperature to which it is cooled, subsequentlyheating the air without the addition of moisture thereto to atemperature which is insufficient to cause said pellets to melt whensaid air contacts with the same but which is high enough to cause anappreciable transfer of moisture from the glue to the air, moving a bedof pellets along a predetermined path and supplying said heated air atone ,aaneoe position along the path of movement thereof to one side ofsaid bed and forcing it through said pellets to the other side of saidbed throughout all portions thereof simultaneously for a time sufficientto form a protective skin on the same, simultaneously agitating thepellets while the air is being forced through said pellets, andthereafter subjecting the pellets 'at a subsequent position of said bedto a higher temperature for removing the remaining moisture from theinterior of the pellets.

12. A glue drying apparatus comprising a reticulated conveyer forconveying glue pellets along a predetermined path; means for forcing adrying medium upwardly through said reticulated conveyer throughoutsubstantially the entire pellet supporting portion thereof from one sideto the other substantially simultaneously, and means for agitating thepellets on said c'on veyer while subjected to the action of said dryingmedium comprising a plurality of agitating members movable relative tosaid conveyer substantially parallel thereto at a greater rate of speedthan said conveyer and independently of the movement of said conveyer,whereby the pellets on said conveyer are agitated substantially at alltimes while supported on said conveyer and irrespective of whether ornot said conveyer is in motion.

13. The method of drying moisture laden glue, which includes the stepsof passing small particles of glue through successive drying zones,agitating said particles as they pass through the first zone, supplyingheated substantially moisture free drying medium to said zones,maintaining the temperature in successive zones at increased degrees,and accurately controlling said temperatures and condition of dryness toprevent melting of the glue and to insure the presence of a non-adhesivesurface on the particles.

14. The methodof drying moisture laden glue which includes the steps ofpassing small particles of glue through a drying zone, cooling a dryingfluid to rid it of moisture, heating the moisture free fluid to apredetermined temperature, passing said heated fluid about the smallparticles of material in said zone, agitating the particles in contactwith said heated fluid, then successively passing said particles throughseparate additional successive zones, applying heated drying fluid tosaid zones, maintaining the temperature in said successive zones atincreased degrees and accurately controlling said temperatures andcondition of dryness to prevent melting of the glue and to insure thepresence of a non-adhesive surface on the particles.

15. An apparatus for drying glue pellets which includes a longitudinallymovable screen conveyor for receiving glue pellets, a drying chamberassociated with said conveyor, means for moving the conveyor in apredetermined direction through said drying chamber, means for coolingair to rid it of moisture, means for heating the moisture ridden airafter it has passed through said cooling means, means for blowing saidheated air veyor, means for supplying a draft of air through the secondconveyor for glue drying purposes, and means for controlling thetemperatures and condition of dryness of the air supplied to saidpellets to prevent melting of the glue and to insure the presence of anon-adhesive surface on the pellets.

16. An apparatus for drying glue pellets which includes a longitudinallymovable screen conveyor for receiving glue pellets, a drying chamberassociated with said conveyor, means for moving the conveyor in apredetermined direction through said drying chamber, means for coolingair to rid it of moisture, means for heating the moisture ridden airafter it has passed through said cooling means, means for blowing saidheated air through the conveyor into the chamber to dry the pellets,means for agitating the pellets carried by said conveyor, said agitatingmeans including means adapted to be moved back and forth in substantialparallel relation to the plane of movement of the conveyor, a secondscreen conveyor upon which pellets may be received from the firstconveyor, means for moving said second screen conveyor in a directionopposite to the first conveyor and beneath said first conveyor, meansfor supplying a draft of air through the second conveyor for glue dryingpurposes, and means for maintaining the temperature in the vicinity ofthe successive conveyors at increased degrees and for controlling saidtemperatures and conditions of dryness of the air contacting with thepellets to prevent melting of the glue and to insure' the presence of anon-adhesive surface on the pellets.

1'7. A glue drying apparatus for drying relatively small particles ofglue comprising a movable longitudinally disposed perforated conveyorfor receiving the particles to be dried, means for moving said conveyor,agitating means mounted in the vicinity of the conveyor, said agitatingmeans being adapted to be moved bodily in a longitudinal direction alonga given path whereby the glue particles positioned on the conveyor willbeengaged by the agitating means, said conveyor passing throughindependent drying zones each having difierent temperatures, thetemperatures of said drying zones being such as to prevent melting ofthe glue particles but to insure the presence of a non-adhesive surfaceon the particles.

18. An apparatus for drying glue pellets which includes a longitudinallymovable screen conveyor for receiving glue pellets, a drying chamberassociated with said conveyor, means for moving the conveyor in apredetermined direction through said drying chamber, means for coolingair to rid it of moisture, means for heating the moisture-riddenair-after it has passed through the cooling means, means for blowingsaid heated air through the conveyor into the chamber to dry thepellets, means for agitating the pellets carried by said conveyor, saidagitating means including means adapted to be moved bodily in alongitudinal direction and in substantial parallel relationship to theplane of movement of the conveyor, a second screen conveyor upon whichpellets may be received from the first conveyor, means for moving thesecond conveyor in a direction opposite to the first conveyor andbeneath said first conveyor, means for supplying a draft through thesecond conveyor for glue drying purposes, and means for controlling thetemperatures and condition of the dryness of the air supplied to saidpellets to prevent melting of the glue pellets and to insure thepresence of a non-adhesive surface on said glue pellets to prevent thepellets from sticking together and forming a homogeneous mass.

THOMAS K. LOWRY..

